1. Field of the Invention
The present invention relates to a heat-generation belt, and a fixing device and an image forming apparatus including therein the heat-generation belt.
2. Description of Related Art
Electrophotographic image forming apparatus have been widely used, with laser beam printers, facsimile machines, copiers, digital multifunctional peripherals and the like being generally known. The image forming apparatus are equipped with a fixing device configured to fix a non-fixed toner image on a toner receiving article.
A known example of such a fixing device is, for example, a fixing device that includes: an endless heat-generation belt, an elastic roll provided on the inner side of the heat-generation belt, a pressure roll for pressing the elastic roll with the intervening heat-generation belt from the exterior of the heat-generation belt, and a power supply for supplying electricity to a resistance heating layer of the heat-generation belt. The fixing device conducts fixing of a toner image by melting the toner image onto the toner receiving article. The resistance heating layer is provided on each of its opposite edges with an annular electrode layer to which electricity is supplied from the power supply. The electrode layer is bonded, for example, to the resistance heating layer (see, for example, Japanese Patent Application Laid-Open No. 2009-109997).
Adequate and stable adhesion strength is required for a long period with regard to the adhesion between the resistance heating layer and the electrode layer. The resistance heating layer is typically composed of a polyimide which can adhere to metals. Adhesion of polyimides to metals, however, is weak.
An exemplary countermeasure for improving the adhesion strength between the resistance heating layer and the electrode layer involves adhesion of the electrode layer to the resistance heating layer by means of chemical bonding, and more specifically, by using a silane coupling agent. Silane coupling agents, however, are readily soluble in a varnish of polyamic acid, a precursor composition for a polyimide. In addition, silane coupling agents are sometimes decomposed at temperatures at which imidation of polyamic acid is effected (for example, 450° C.). Accordingly, adhesion of the electrode layer to the resistance heating layer using a silane coupling agent may lead to generation of some non-bonded parts resulting the heat-generation belt exhibiting unstable resistance heating.